The phosphoinositide 3-kinases (PI3Ks) belong to a large family of lipid signaling kinases that phosphorylate phosphoinositides at the D3 position of the inositol ring (Cantley, Science, 2002, 296(5573): 1655-7). The compound (S)-7-(1-((9H-purin-6-yl)amino)ethyl)-6-(3-fluorophenyl)-3-methyl-5H-thiazolo[3,2-a]pyrimidin-5-one is an inhibitor of PI3Ks, including PI3Kδ, and is previously described in U.S. Pat. No. 8,940,752, which is incorporated by reference herein in its entirety.
PI3K isoforms are believed to be involved in cancer. For example, the gene encoding p110α is mutated frequently in common cancers, including breast, prostate, colon and endometrial (Samuels, et al., Science, 2004, 304(5670):554; Samuels, et al., Curr Opin Oncol. 2006, 18(1):77-82). Thus, inhibitors of PI3Ks, such as (S)-7-(1-((9H-purin-6-yl)amino)ethyl)-6-(3-fluorophenyl)-3-methyl-5H-thiazolo[3,2-a]pyrimidin-5-one, are potentially useful as cancer therapeutics. Accordingly, efficient and scalable syntheses are needed for producing this drug compound. The processes and intermediates provided herein are directed to this need.